Let's get to first principles first:
Article 1 of the US Constitution is quite clear "people", not citizen, resident, non-immigrants, etc. is how the electors for Congress are described. So how do they become "electors"?
Section 2, paragraph 1 (for the house of representatives but it drives all other qualifications unless the Senate adopts a different system for itself [Section 3, para 1]) indicates that "electors shall have the qualification required of electors of the most numerous branch of the State"
It is the various States that define and decide who THEIR electors are to be for their state, and by ricochet, for the US congress.
There is, and never was, any specific requirement in the Constitution for those electors to be citizens of the US. Therefore, it is quite fair for any state, including California, to decide for itself that anyone residing in their state, as demonstrated by holding a valid driver licence amongst other things, shall be sufficient to have an interest in the affairs of the State justifying having the right to vote.
There are many countries, including Canada, that make being either a Citizen or a landed immigrant as requirement to vote, but not the US Constitution.
That's it, that's all.